There has been a serious erosion problem with valves used in high temperature erosive solid or fluid flow in that the valve seat or portions of the valve seat are eroded or abraded away by the flow causing leaks and a failure of the valve to shut-off flow when desired. In addition, there is a problem with valves used for high temperature erosive or abrasive flows to provide adequate seating and hence sealing of the valve member on the valve seat due to thermal growth caused by the extremely high temperatures.